# name : ggplot2 panel setting, major/minor grid
# key : ggplot2.panel.setting
# key : panel.setting#ggplot2
# contributor : Shuguang Sun
# --
theme(
panel.grid.major = element_blank(),
panel.grid.minor = element_blank(),
panel.border = element_blank(),
panel.background = element_blank(),
axis.line = element_line(color = "black")
)